Permeability and expansibility of sodium bentonite in dilute solutions
2010 (English)In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, Vol. 358, no 1-3, 68-78 p.Article in journal (Refereed) Published
In developing the dynamic force balance model for colloidal expansion, it was acknowledged that accurate description of the viscous drag force, or equivalently the permeability, is very important to describe the swelling process of compacted bentonite as it expands and eventually turns from a gel into a sol in low ionic strength waters. We therefore developed a Kozeny-Carman-like equation to quantify the permeability of the purified and fully Na-exchanged bentonite in dilute homoionic solutions, based on a set of permeability measurements. The force balance model, together with a friction model derived from the permeability, is then validated against accurate observations of the expansion process of the Na-exchanged bentonite in a water filled vertical test tube. The expansion is followed in detail over a month, by use of the magnetic resonance imaging technique with a spatial resolution of 0.2 mm. as an initially compacted tablet of Na-bentonite expands in water. The model accurately predicts not only the expansion rate and the general features of the expansion but also the basic behaviour at the expanding gel/sol interface. In addition, the use of the developed Kozeny-Carman-like equation substantiates that the expansion rate depends strongly on the friction of the particles against the water.
Place, publisher, year, edition, pages
2010. Vol. 358, no 1-3, 68-78 p.
Force balance model, Friction model, Permeability model, Sodium, bentonite, Colloidal expansion, van der Waals force, Double layer, force, Constant charge, kozeny-carman equation, plate-like particles, hydraulic conductivity, molecular-dynamics, cake filtration, water, clay, diffusion, montmorillonite, dispersions
Other Engineering and Technologies not elsewhere specified
IdentifiersURN: urn:nbn:se:kth:diva-19354DOI: 10.1016/j.colsurfa.2010.01.033ISI: 000276115100010ScopusID: 2-s2.0-76749125762OAI: oai:DiVA.org:kth-19354DiVA: diva2:337401
QC 20100525 Korrigering:
"In the above-mentioned article, all the experimental data presented in Figs. 5–8 were obtained from Prof. István Furó and Dr. Sergey V. Dvinskikh. These data were published as an integral part of a technical report  of the Swedish Nuclear Fuel and Waste Management Company (SKB), TR-09-27, publicly available through the publication download server at the homepage of SKB (see “Publications” at http://www.skb.se). Regrettably, proper reference to this report was not given in the article which thereby may have created the incorrect impression that the experimental data had been obtained within the framework of the author's study". I COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, vol. 358, s. 68(20101213)